Real-time dielectric relaxation in glassy polyvinylacetate.

Abstract

The discharge current measured for glassy polyvinylacetate is expressed by employing the Kohlrausch law as the dielectric response function over the whole range of times used, 3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$/${\ensuremath{\tau}}^{\mathrm{*}}$${10}^{3}$, where ${\ensuremath{\tau}}^{\mathrm{*}}$ is the Kohlrausch relaxation time, if another type of decay observed at longer times, most likely due to electrode polarization of the Cole-Davidson type, is properly eliminated. However, it is shown from a precision measurement of the complex permittivity that at Tg${T}_{g}$ the short-time behavior of the response function is slightly but evidently different from that of the Kohlrausch function.